Salmonella causes serious and sometimes fatal infections, especially in young children, the elderly and people with weakened immune systems. It is generally contracted from contaminated poultry, meat, eggs and water, and affects the intestinal tract.

Chickens can pass the bacteria to eggs because eggs leave hens through the same passageway as feces. Alternatively, bacteria in the hen’s ovary or oviduct can get to the egg before the shell forms around it.